The goal of this project is to provide support of National Toxicology Program (NTP) hazard identification activities targeted toward the prevention of diseases or adverse effects caused by exposure to chemical or physical agents. Toxicity testing is an important aspect of public health research in that it serves to identify chemicals that are hazardous to human health. This program is designed to evaluate toxicity following early life exposure to chemicals. For this project, laboratory rats and mice are exposed to various test materials during fetal development and exposures continue after birth and through adulthood. Animals are evaluated for adverse effects at different stages of life for effects such as birth defects, changes in onset of puberty, infertility or other reproductive toxicity such as adverse effects on reproductive organs including ovaries or testes, and development of tumors.